A pic would help, but most shocks can be disassembled. There should be a plate at the top of the shock with a notch in it. The notch slides around the shaft of the plunger, and then the plate fits into place at the top of the shock when the spring pushes against it. When the spring is compressed you can slide the plate out, and then the spring can be removed. Clean everything back up, then reassemble in the same manner.
You will need a spring compressor, or a strong stomach, to compress the spring. I don't have a spring compressor to fit small springs like these, so I just fold up a towel, put it over my stomach, and position the lower end of the shock against my stomach. Then, pulling with two hands, I can compress the spring enough to slip the plate out. Putting it back in usually requires a helper. You don't have to be a muscle man to do this either. I'm only 5'10" and 170 lbs.
Good luck.
Camelman